It is known for the shaft of such a tool to be held in a central receiving opening of an annular, self-contained part, most often embodied as a tube part, of a tool holder by means of a press fit. This tube part forms the end toward the tool of a tool holder of otherwise conventional design.
This tube part of the tool holder can be widened by heating so far in the radial direction that the cold shaft of the tool can be thrust into the tube part or pulled out of it. As soon as the tube part has cooled down again, a pressure bond between it and the shaft of the tool, by means of which pressure bond the tool is reliably fixed in the tool holder (shrink-fit technology; see for example EP 1 353 768 B1).
Alternatively, chucking can also be done hydraulically. For that purpose, inside the aforementioned tube part of the tool holder, a hydraulic clamping device is provided, which upon imposition of hydraulic pressure reduces its inside diameter embracing the tool shaft and thus chucks the tool shaft by frictional engagement.
So-called collet chucks are a further alternative; in them, the tool shaft is kept clamped by frictional engagement with the aid of a collet, by driving the collet, which is provided with an outer cone, into a complementary conical seat and thereby causing it to close.
It is also known for tools in the form of so-called cutter heads to be connected by positive engagement, with the aid of a usually central set screw and one or preferably more drivers to the tool holder, which here is usually called a cutter head receptacle.
Collet chucks of the type described have proved themselves very well in practice.
In general in collet chucks of the described type, there is the problem that under unfavorable circumstances, because of reaction forces that originate at the cutting edges of the tool, vibration is induced, which not infrequently is in or near the resonant range. Such vibration arises because the tool cutting edges are exposed to rapidly alternating stresses, for instance because in rapid succession, n and n+1 cutting edges mesh with one another in alternation. This vibration can make itself felt so markedly in the complete system comprising the tool, collet chuck and machine tool, that the cutting speed, for instance, and/or other cutting parameters have to be reduced, which impairs the performance of the concrete system and is therefore unwanted.
It is known that the tendency to vibration of such a complete system can be favorably affected in some cases by “softer” chucking of the tool.
It is the object of the present invention to disclose a means which makes chucking the tool in a way that especially favorably affects the vibration behavior of the tool, without making compromises in the machining precision.